<template>
  <div @click="onHeaderClick">
    <div class="oolong-tag oolong-tag-checked" v-for="(item,index) in selectedMultiple" :key="index">
      <span class="oolong-tag-text">{{ item.label }}</span>
      <oolongIcon type="ios-close-empty" @click.native.stop="removeTag(item)"></oolongIcon>
    </div>
    <span
      :class="singleDisplayClasses"
      v-show="singleDisplayValue"
    >{{ singleDisplayValue }}</span>
    <input
      :id="inputElementId"
      type="text"
      v-if="filterable"
      v-model="query"
      :disabled="disabled"
      :class="[prefixCls + '-input']"
      :placeholder="showPlaceholder ? localePlaceholder : ''"
      :style="inputStyle"
      autocomplete="off"
      spellcheck="false"
      @keydown="resetInputState"
      @keydown.delete="handleInputDelete"
      @focus="onInputFocus"
      @blur="onInputFocus"

      ref="input">
    <oolongIcon type="ios-close" :class="[prefixCls + '-arrow']" v-if="resetSelect"
                @click.native.stop="onClear"></oolongIcon>
    <oolongIcon type="arrow-down-b" :class="[prefixCls + '-arrow']"
                v-if="!resetSelect && !remote && !disabled"></oolongIcon>
  </div>
</template>
<script>
import oolongIcon from '../icon';
import Emitter from '../../mixins/emitter';
import Locale from '../../mixins/locale';

const prefixCls = 'oolong-select';

export default {
  name: 'oolongSelectHead',
  mixins: [Emitter, Locale],
  components: {oolongIcon},
  props: {
    disabled: {
      type: Boolean,
      default: false
    },
    filterable: {
      type: Boolean,
      default: false
    },
    multiple: {
      type: Boolean,
      default: false
    },
    remote: {
      type: Boolean,
      default: false
    },
    initialLabel: {
      type: String
    },
    values: {
      type: Array,
      default: () => []
    },
    clearable: {
      type: [Function, Boolean],
      default: false
    },
    inputElementId: {
      type: String
    },
    placeholder: {
      type: String
    },
    queryProp: {
      type: String,
      default: ''
    }
  },
  data() {
    return {
      prefixCls: prefixCls,
      query: '',
      inputLength: 20,
      remoteInitialLabel: this.initialLabel,
      preventRemoteCall: false
    };
  },
  computed: {
    singleDisplayClasses() {
      const {filterable, multiple, showPlaceholder} = this;
      return [{
        [prefixCls + '-placeholder']: showPlaceholder && !filterable,
        [prefixCls + '-selected-value']: !showPlaceholder && !multiple && !filterable
      }];
    },
    singleDisplayValue() {
      if ((this.multiple && this.values.length > 0) || this.filterable) return '';
      return `${this.selectedSingle}` || this.localePlaceholder;
    },
    showPlaceholder() {
      let status = false;
      if (!this.multiple) {
        const value = this.values[0];
        if (typeof value === 'undefined' || String(value).trim() === '') {
          status = !this.remoteInitialLabel;
        }
      } else {
        if (!this.values.length > 0) {
          status = true;
        }
      }
      return status;
    },
    resetSelect() {
      return !this.showPlaceholder && this.clearable;
    },
    inputStyle() {
      let style = {};

      if (this.multiple) {
        if (this.showPlaceholder) {
          style.width = '100%';
        } else {
          style.width = `${this.inputLength}px`;
        }
      }

      return style;
    },
    localePlaceholder() {
      if (this.placeholder === undefined) {
        return this.t('i.select.placeholder');
      } else {
        return this.placeholder;
      }
    },
    selectedSingle() {
      const selected = this.values[0];
      return selected ? selected.label : (this.remoteInitialLabel || '');
    },
    selectedMultiple() {
      return this.multiple ? this.values : [];
    }
  },
  methods: {
    onInputFocus(e) {
      this.$emit(e.type === 'focus' ? 'on-input-focus' : 'on-input-blur');
    },
    removeTag(value) {
      if (this.disabled) return false;
      this.dispatch('oolongSelect', 'on-select-selected', value);
    },
    resetInputState() {
      this.inputLength = this.$refs.input.value.length * 12 + 20;
    },
    handleInputDelete() {
      if (this.multiple && this.selectedMultiple.length && this.query === '') {
        this.removeTag(this.selectedMultiple[this.selectedMultiple.length - 1]);
      }
    },
    onHeaderClick(e) {
      if (this.filterable && e.target === this.$el) {
        this.$refs.input.focus();
      }
    },
    onClear() {
      this.$emit('on-clear');
    }
  },
  watch: {
    values([value]) {
      if (!this.filterable) return;
      this.preventRemoteCall = true;
      if (this.multiple) {
        this.query = '';
        this.preventRemoteCall = false; // this should be after the query change setter above
        return;
      }
      // #982
      if (typeof value === 'undefined' || value === '' || value === null) this.query = '';
      else this.query = value.label;
      // eslint-disable-next-line no-return-assign
      this.$nextTick(() => this.preventRemoteCall = false); // this should be after the query change setter above
    },
    query(val) {
      if (this.preventRemoteCall) {
        this.preventRemoteCall = false;
        return;
      }

      this.$emit('on-query-change', val);
    },
    queryProp(query) {
      if (query !== this.query) this.query = query;
    }
  }
};
</script>
